Multisheave blocks



Oct. 4, 1966 w. M. MARKS ETAL 3,276,749

MULTISHEAVE BLOCKS Filed OCT '7, 1964 3 Sheets-Sheet l WILL/AM M. MARKSJAMES E. AsHvvomH WAYNE L. BRACK/N INVENTORS ATTORNEYS BY W My Oct; 4,1966 w. M. MARKS ETAL MULTISHEAVE BLOCKS 5 Sheets-Sheet 2 Filed Oct. 7,1964 'W/LL/AMM. MARKS JAMES E. ASA/WORTH WAYNE L. BRAcK/N INVENTORSATTORNEYS BY @W? W,

Oct. 4, 1966 w. M. MARKS ETAL 3,276,749

MULTI SHEAVE BLOCKS Filed Oct. 7, 1964 5 Shets$heet 5 WILL/AM M. MARKSJAMES E. ASP/WORTH WAYNE L. BRACK INVENTORS M ATTORNEYS United StatesPatent 3,276,749 MULTISHEAVE BLOCKS William M. Marks, James E. Ashworth,and Wayne L.

Brackin, Beaumont, Tex., assignors to Dresser Industries, Inc., acorporation of Delaware Filed Oct. '7, 1964, Ser. No. 402,121 8 Claims.(Cl. 254-188) This invention relates to a multisheave block generally,and, in particular, to multisheave traveling blocks where a change inthe number of sheaves in use can affect the centerline of support of theblock.

This invention has utility in any application where a multisheave blockis used to move a load and it is desirable to keep the centerline ofsupport of the block in,

line with the center of gravity of the load it is supporting. Thisinvention has particular utility, however, in the drilling industrywhere during the total weight of pipe, to be handled by the hoistingequipment of the drilling rig, increases as the well gets deeper. It iscommon practice in the drilling industry not to change traveling blocksas the pipe weight increases, but to use a multisheave traveling blockand crown block and to string morel-ines between these two members asthe load increases. Thus at the beginning of drilling operations, thereusually will be some sheaves in both the crown block and traveling blockwhich will not be in service. With many traveling blocks it is possibleto maintain the centerline of support of the block in alignment with thecenter of gravity of the load it is carrying, by properly selecting thesheaves to be reeved. However, there are occasions where it is notpossible to do this.

Therefore, it is an object of this invention to provide a travelingblock having a laterally adjustable centerline of support.

It is another object of this invention to provide a traveling block whencan adjust its centerline of support laterally when required by a changein the number of its sheaves in service.

It is another object of this invention to provide a multishe'avetraveling block and hook assembly having a detachable sheave, which isnot mounted for rotation on the same horizontal axis as the othersheaves, with the centerline of the block being movable laterally toadjust the centerline of support of the block as required by the removalof the detachable she-ave.

It is another object of this invention 'to provide a multisheavetraveling block for supporting a hook with the centerline of support ofthe block being movable laterally to maintain it in line with thecenterline of the load carried by the hook as the number of sheavessupporting the hook is changed.

These and other objects, advantages, and features of the invention willbe apparent to one skilled in the art from a consideration of thisspecification, appended claims, and attached drawings.

To obtain these objectives, in -accordance with this invention, at leasta portion of the sheaves of the traveling block are mounted for lateralmovement relative to the center of gravity of the load they arecarrying. Thus, when the number of sheaves in service is increased ordecreased, at least a portion of these sheaves can be adjustedlaterally, as required, to maintain the centerline of support of theblock in the desired position relative to whatever load the block issupporting.

The invention will now be described, in detail, in connection with theembodiment of the invention shown in the attached drawings in which,

FIGURE 1 is a side view of a traveling block and hook assembly, theblock, being of the type commonly referred to as a split block, having adetachable sheave, which is located in a plane transverse the plane ofthe rest of the sheaves making up the block;

FIGURE 2 is a side view of the traveling block and hook assembly ofFIGURE 1 with the detachable sheave removed and the other sheavesshifted laterally to maintain the centerline of support of the block inline with the downward load imposed on the block by the hook assembly sothat no turning moment or other undesirable stresses will be imposed byeither member on the connection between the two;

FIGURE 3 is a front view of the hook assembly of FIGURE 2, illustratingthe arrangement of the sheaves in the two spaced sheave cases which formopposite sides of the vertical opening extending through the block andalso illustrating the method used in this embodiment for attaching thesheaves to the support base of the block for lateral movement relativeto the support base;

FIGURE 4 is a sectional view taken along line 44 of FIGURE 1 show-ingthe connection between one of the sheave cases -and the support base ofthe block to better illustrate the connection therebetween;

FIGURE 5 is a view taken along line 55 of FIGURE 1 illustrating themeans employed in this embodiment of the invention to move a portion ofthe sheaves of the block laterally relative to the support base to shiftthe centerline of support of the block relative to the base when thesesheaves are in service; and

FIGURE 6 is a view taken along lines 6-6 of FIG- UR'E 5 showing a sideview of the shifting means employed in this embodiment of thisinvention.

Split blocks of the typeshown in the attached drawings accentuate theproblem of a shifting centerline of support because of their uniquearrangement of the sheaves. In these blocks the sheaves are mounted forrotation around two separate horizontal axes. With this arrangement,when some -or all of the sheaves rotating around one axis are taken outof service, the lateral shift in the centerline of support of the blockis considerable.

Thus, in the split type block shown in the drawings,

which is generally indicated by the number 10, three.

sheave cases 11, 12 and 13 are arranged with sleeve cases 11 and 12 inspaced, parallel, relationship and sheave case 13 located adjacent theends of the other two and extending transversely between them. Eachsheave case may contain any number of sheaves. In the embodiment shown,sheave cases 11 and 12 are provided with three sheaves each, the sheavesbeing generally indicated by the number 14, whereas case 13 containsonly sheave 17 to provide a total of seven sheaves for the travelingblock.

The sheaves 14 are mounted for rotation on shafts 15 and 16 whoselongitudinal axes are in alignment so that the sheaves 14 all rotatearound the same horizontal axis, which is generally indicated by thenumber 19. S'heave 17, however, in sheave case 13 is mounted to rotatearound a horizontal axis, which, in the embodiment shown, intersects theaxis of the rotation of the other sheaves but is perpendicular thereto.Thus, when the detachable sheave case 13 is attached to the block andall the sheaves are strung in the manner shown in FIGURE 1, thecenterline of support of the block, generally indicated by the number18, is located between sheave case 13 and horizontal axis 19 of thesheaves 14 and equidistant between sheave cases 11 and 12.

As explained above, it is desirable, for the centerline of support ofthe block to be in line with the load which is imposed on the block. Inthe embodiment shown, traveling block 10 has attached thereto a springhook assembly generally indicated by the number 20.

In the hook assembly shown, the hook portion 20a is pivotally attachedto spring housing 27 to pivot around horizontal axis 24. This allows theelevator link supporting cars 21 and 22 to be laterally offset from theswivel bail supporting portion 23 yet each, when loaded will rotate thehook section 20a around axis 24 until the center of gravity of the loadis in vertical alignment with axis 24.

For example, as shown in FIGURES 1 and 2 elevator links 25 and 26 are invertical alignment with axis 24 and with the vertical axis of the springhousing 27 of the hook aseembly. When the swivel bail (not shown) ispicked up by the swivel bail supporting section 23, then the hook willpivot around horizontal axis 24 until the swivel bail is supported inline with the vertical axis of the hook assembly. Thus, whether the loadis imposed upon the hook by elevator links 25 and 26 or by a swivelhail, the resultant line of force of the load will be the same. If thisline of force coincides with the centerline of support 18 of block nounbalanced forces will be imposed on the hook and block assembly or onany of the portions of drilling lines 28 which extend from the crownblock (not shown) to the sheaves on the traveling block. If they do notcoincide a turning moment will be imposed on the block and hookassembly.

For a complete description of this hook assembly, see co-pending patentapplication entitled Hook Assembly which was filed on October 7, 1964,and given Serial Number 402,070.

Early in the drilling operations of a well it is not usually necessaryor desirable to have all of the sheaves of the traveling and crown blockin operation. For example, in the initial stages of drilling operationswith a block of the type shown in the drawings only eight lines or foursheaves may be necessary to support the load imposed on the block. Itis, of course, desirable to keep the number of lines strung between thecrown block and the traveling block to a minimum for as the number oflines increases, the speed of the traveling block for a given hoistingrate decreases, and speed of movement of the traveling block is veryimportant when moving pipe in and out of the hole.

Therefore, assume in the initial stages of drilling operations twosheaves in each of sheave cases 11 and 12 are in service. The sheaves touse can easily be chosen to maintain centerline of support 18,equidistant between sheave cases 11 and 12. For example, as shown inFIG- URE 3, with the out-board and in-board sheaves of each sheave casein service, centerline of support 18 of the block is located equidistantbetween sheave cases 11 and 12. The centerline of support, however, willnot remain located between horizontal axis 19 and sheave case 13, as wasthe case in FIGURE 1 when all sheaves were in operation, but will shiftto intersect axis 19 around which all of the sheaves in operation arerotating. Thus, with the block assembled as shown in FIGURE 1, but withonly four sheaves in service, the new centerline of support of the block18 is out of alignment with the resultant line of force of the load, adistance c. This eccentricity e would cause the block and hook assemblyto tend to rotate to compensate for it and result in unbalanced loadingon various members of the assembly.

Therefore, in accordance with this invention, means are provided formoving the sheaves of the block laterally with respect to the loadimposed on the block to shift the centerline of support of the blockinto vertical alignment with the load. In the embodiment shown, sheavecases 11 and 12 are attached to support base 30, by means of removablepins which extend laterally through the sheave cases and openings in thesupport base. The support base holds the sheave cases in spacedrelationship, and also connects the sheave cases to hook assembly 27.Only pins 31 and 32, which are employed to attach sheave case 11 to base30 and pin 29 which attaches sheave case 13 to base 30, are shown in thedrawings. Two pins per sheave case are used in the embodiment shown andeach connection is generally the same, therefore, only one will bedescribed in detail.

The details of the connection between sheave case 11 and support base 30is shown in FIGURE 4 where a vertical section through pin 31 is shown.Thus, sheave case 11 is provided with two vertical side plates 11a and11b between which the sheaves are rotatably mounted. Support base '30 isprovided with upwardly extending flange 33 which is located between theside plates. Spacers 34 and 35 are positioned between the side platesand flange 33 and all of the components making up the connection, sideplates, spacers and upwardly extending flange, are provided withopenings which can be positioned in alignment to receive pin 31 in themanner shown in the drawings. Pin 31 is held in position in the openingby cap screw 36 which engages a tapped hole in the end of pin 31 andholds the pin against washer 37, which is attached, as by welding, tothe outside surface of side plate 11a.

In accordance with the invention, means are provided to mount thesheaves so that their position relative to support base 30 can bechanged. In the embodiment shown, spacer 34 is attached to the insidesurface of plate 11a and has laterally extending bearing member 38attached thereto. The bearing member is positioned to en gage the uppersurface of flange 33 and slidably support the sheave case on the flange.Thus, by providing a plurality of appropriately spaced openings inflange 33, sheave case 11 can be moved laterally to a variety ofpositions relative to the support base.

In the embodiment shown, two pins such as pin 31 are employed to attacheach sheave case to support member 30. Therefore, only four holes ineach flange 3B are necessary to shift sheave case 11 and 12 intoposition to maintain the centerline of support of the block in verticalalignment with the load imposed thereon. In other words, with the blockshown in the drawings, it is contemplated that the centerline of support18 of the block will be either along line 18 as when sheave 17 is inservice, or along line 18' when sheave 17 is not in service. Theretore,only two positions for sheave cases 11 and 12 are required: the oneshown in FIGURE 1 and the one shown in FIGURE 2 when sheaves 14 havebeen moved laterally relative to the load (hook assembly '20 in thiscase) until its centerline of support 18 is in line with the centerlineof the load along line 18".

Means are also provided for moving at least a portion of the sheaves ofthe block in service laterally relative to the load the block issupporting to maintain the centerline of support of the block in linewith the center of gravity of the load as required by changes in thesheaves in service. In the embodiment illustrated, it is desirable toshift both sheave cases 11 and 12 and in this embodiment each sheavecase is provided with its own shifting means. They are both the same,therefore, only the one employed to shift sheave case 11 is shown andwill be described in detail.

AS shown in FIGURES 5 and 6, rack 40 is attached to the top of upwardlyextending flange 33 on support base 30. The rack should be long enoughto provide adequate movement to the sheave case. Rotatably mounted inside plates 11a and 11b of sheave case 11 and extending laterally acrossrack 40 is pinion shaft 41 which supports pinion 42 in engagement withrack 40. Pinion 42 is 'keyed or otherwise connected to pinion shaft 4 1so rotation of the shaft will rotate the pinion. The shaft is providedwith hexagonal head portion 43 to receive a wrench socket (not shown) torotate the shaft and the pinion in the desired direction to move sheavecase 11 relative to support base 30.

For example, assume that the Well has reached a point where it isnecessary to employ all the sheaves of the block, or, possibly, it istime to run a casing string which has considerable weight. Therefore,sheave case 16 with extra sheave @17 is to be added to the assembly. Inthe embodiment illustrated, this is accomplished, while maintaining thecenter of support of the block in vertical align ment with the hookassembly, as follows: Pins 31 and 32 are removed from the holes in whichthey are located in flange 33. A wrench is then attached to hexagonalhead 43 and pinion shaft 41 and pinion 42 is rotated in the properdirection to move pinion 41 along rack 40 and, consequently, move sheavecase '11, laterally, relative to support base 30 until the other set ofopenings provided in flange 33 are in alignment with the pin openings inthe side plates 11a and 11b of the sheave case. The pins are thenreassembled through flange 33. This same procedure is followed inconnection with sheave case 12 and the block is ready to receive sheavecase '13. The cen terline of support 18 of the block is now between thehorizontal axis of rotation of the sheaves of sheave oases 11 and 12,and sheave case113 and in line with the line of force imposed on theblock by hook assembly 20, in the manner shown in FIGURE 1.

When moving the sheave cases back and forth, and removing and addingsheaves etc., the sheave guards will need to be rearranged somewhat tomaintain the proper appearance for the block and also to maintain asmooth outer surface so the block will not tend to snag something as itmoves up and down in the derrick. Typical guard arrangements for thistype block are shown in the drawings.

From the foregoing, it will be seen that this invention is one welladapted to attain all of the ends and obiects hereinabove set forth,together with other advantages which are obvious and which are inherentto the apparatus and structure.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as il1usstrative and not in a limiting sense.

The invention having been described, what is claimed 1. A travelingblock provided with a plurality of sheaves divided into two groups witheach group of sheaves mounted for rotation around two differenthorizontal axes, the block having a first centerline of support when allof the sheaves are in service and a second centerline of support whenonly the sheaves in one group are in service; means for connecting theblock to a load; and means for moving the group of sheaves in servicelaterally relative to the connecting means to maintain the secondcenterline of support in alignment with the load.

2. A traveling block having a plurality of sheaves arranged in groups torotate around at least two different horizontal axes; the block having afirst centerline of support when all of the sheaves are in service andat least one other centerline of support when less than all of thesheaves are in service; means for connecting the sheaves in service to aload; and means for moving laterally a portion of the sheaves in serviceto maintain the centerline of support of the block in alignment with thecenter of gravity of a load as required by changes in the number ofsheaves in service.

3. A multisheave traveling block, for supporting a hook assembly, havinga group of sheaves mounted for rotation around a horizontal axis and atransverse sheave located on one side of the group of sheaves andmounted for rotation around another horizontal axis, thereby providingthe block with a laterally shifted centerline of support when thetransverse sheave is not in service; and means for moving the firstmentioned group of sheaves laterally toward the location of thetransverse sheave when it is not in service to maintain the samecenterline of support between the block and a hook it supports, when thetransverse sheave is not in service.

4. The traveling block of claim 3 in which the transverse sheave isremovably attached to the block to allow it to be removed when not inservice.

5. A split traveling block comprising at least two parallel sheavesspaced apart sufiiciently to provide a vertically extending openingthrough the block through which pipe can extend as the block movesvertically relative to the pipe, and a third sheave positionedtransverse to the two parallel sheaves at one side of the openingthrough the block; the block having a first centerline of support whenonly the two parallel sheaves are in service and a second centerline ofsupport laterally shifted from the first when all of the sheaves are inservice; and means for positioning the two parallel sheaves laterally toadjust the first centerline of support of the block laterally intoalignment with the second centerline of support when the third sheave isnot in service.

6. The traveling block of claim 5 in which the third sheave is removablyattached to the block to allow it to be removed when not in service.

7. A traveling block having a plurality of sheaves divided into threegroups of at least one sheave each, the sheaves of two groups beingmounted to rotate on the same horizontal axis with the two groups inspaced, parallel relationship to provide a vertically extending slotthrough the block through which pipe can extend as the block movesvertically relative to the pipe; the third group of sheaves beingpositioned transverse the opening on one side thereof and mounted torotate on an axis perpendicular to the axis of rotation of the other twogroups to provide the block with a first centerline of support when allof the sheaves are in service and a second centerline of supportlaterally spaced from the first when the sheaves in the third group arenot in service; a support base for connecting the sheaves to a load; andmeans for moving the two parallel groups of sheaves laterally toward theposition of the third group when the sheaves in the third group are notin service to shift the second centerline of support into alignment withthe first centerline of sup port, and to shift the two parallel groupsof sheaves laterally away from the position of the third group when thesheaves in the third group are in service.

8. The traveling block of claim 7 further provided with two parallelracks mounted on the support base, one adjacent each of the groups ofsheaves in parallel relationship and a pinion rotatably supported byeach of said groups, each pinion being in engagement with one of theracks for moving the groups of sheaves by rotation of the pmrons.

References Cited by the Examiner UNITED STATES PATENTS 3,179,376 4/1965Botten 254l88 SAMUEL F. COLEMAN, Primary Examiner.

1. A TRAVELING BLOCK PROVIDED WITH A PLURALITY OF SHEAVES DIVIDED INTOTWO GROUPS WITH EACH GROUP OF SHEAVES MOUNTED FOR ROTATION AROUND TWODIFFERENT HORIZONTAL AXES, THE BLOCK HAVING A FIRST CENTERLINE OFSUPPORT WHEN ALL OF THE SHEAVES ARE IN SERVICE AND A SECOND CENTERLINEOF SUPPORT WHEN ONLY THE SHEAVES IN ONE GROUP ARE IN SERVICE; MEANS FORCONNECTING THE BLOCK TO A LOAD; AND MEANS FOR MOVING THE GROUP OFSHEAVES IN SERVICE LATERALLY RELATIVE TO THE CONNECTING MEANS TOMAINTAIN THE SECOND CENTERLINE OF SUPPORT IN ALIGNMENT WITH THE LOAD.